Annotation of embedaddon/curl/docs/libcurl/opts/CURLOPT_CONNECT_TO.3, revision 1.1
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! 23: .TH CURLOPT_CONNECT_TO 3 "March 23, 2020" "libcurl 7.70.0" "curl_easy_setopt options"
! 24:
! 25: .SH NAME
! 26: CURLOPT_CONNECT_TO \- Connect to a specific host and port instead of the URL's host and port
! 27: .SH SYNOPSIS
! 28: .nf
! 29: #include <curl/curl.h>
! 30:
! 31: CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CONNECT_TO,
! 32: struct curl_slist *connect_to);
! 33: .fi
! 34: .SH DESCRIPTION
! 35: Pass a pointer to a linked list of strings with "connect to" information to
! 36: use for establishing network connections with this handle. The linked list
! 37: should be a fully valid list of \fBstruct curl_slist\fP structs properly
! 38: filled in. Use \fIcurl_slist_append(3)\fP to create the list and
! 39: \fIcurl_slist_free_all(3)\fP to clean up an entire list.
! 40:
! 41: Each single string should be written using the format
! 42: HOST:PORT:CONNECT-TO-HOST:CONNECT-TO-PORT where HOST is the host of the
! 43: request, PORT is the port of the request, CONNECT-TO-HOST is the host name to
! 44: connect to, and CONNECT-TO-PORT is the port to connect to.
! 45:
! 46: The first string that matches the request's host and port is used.
! 47:
! 48: Dotted numerical IP addresses are supported for HOST and CONNECT-TO-HOST.
! 49: A numerical IPv6 address must be written within [brackets].
! 50:
! 51: Any of the four values may be empty. When the HOST or PORT is empty, the host
! 52: or port will always match (the request's host or port is ignored).
! 53: When CONNECT-TO-HOST or CONNECT-TO-PORT is empty, the "connect to" feature
! 54: will be disabled for the host or port, and the request's host or port will be
! 55: used to establish the network connection.
! 56:
! 57: This option is suitable to direct the request at a specific server, e.g. at a
! 58: specific cluster node in a cluster of servers.
! 59:
! 60: The "connect to" host and port are only used to establish the network
! 61: connection. They do NOT affect the host and port that are used for TLS/SSL
! 62: (e.g. SNI, certificate verification) or for the application protocols.
! 63:
! 64: In contrast to \fICURLOPT_RESOLVE(3)\fP, the option
! 65: \fICURLOPT_CONNECT_TO(3)\fP does not pre-populate the DNS cache and therefore
! 66: it does not affect future transfers of other easy handles that have been added
! 67: to the same multi handle.
! 68:
! 69: The "connect to" host and port are ignored if they are equal to the host and
! 70: the port in the request URL, because connecting to the host and the port in
! 71: the request URL is the default behavior.
! 72:
! 73: If an HTTP proxy is used for a request having a special "connect to" host or
! 74: port, and the "connect to" host or port differs from the request's host and
! 75: port, the HTTP proxy is automatically switched to tunnel mode for this
! 76: specific request. This is necessary because it is not possible to connect to a
! 77: specific host or port in normal (non-tunnel) mode.
! 78:
! 79: When this option is passed to \fIcurl_easy_setopt(3)\fP, libcurl will not copy
! 80: the entire list so you \fBmust\fP keep it around until you no longer use this
! 81: \fIhandle\fP for a transfer before you call \fIcurl_slist_free_all(3)\fP on
! 82: the list.
! 83:
! 84: .SH DEFAULT
! 85: NULL
! 86: .SH PROTOCOLS
! 87: All
! 88: .SH EXAMPLE
! 89: .nf
! 90: CURL *curl;
! 91: struct curl_slist *connect_to = NULL;
! 92: connect_to = curl_slist_append(NULL, "example.com::server1.example.com:");
! 93:
! 94: curl = curl_easy_init();
! 95: if(curl) {
! 96: curl_easy_setopt(curl, CURLOPT_CONNECT_TO, connect_to);
! 97: curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
! 98:
! 99: curl_easy_perform(curl);
! 100:
! 101: /* always cleanup */
! 102: curl_easy_cleanup(curl);
! 103: }
! 104:
! 105: curl_slist_free_all(connect_to);
! 106: .fi
! 107: .SH AVAILABILITY
! 108: Added in 7.49.0
! 109: .SH RETURN VALUE
! 110: Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
! 111: .SH "SEE ALSO"
! 112: .BR CURLOPT_URL "(3), " CURLOPT_RESOLVE "(3), " CURLOPT_FOLLOWLOCATION "(3), " CURLOPT_HTTPPROXYTUNNEL "(3), "
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